The ulna is a long bone, prismatic in form, that is situated at the medial side of the forearm, parallel with the radius. The ulna is divisible into a body and two extremities. Its upper extremity, of great thickness and strength, forms a large part of the elbow-joint; the bone diminishes in size from above downward, its lower extremity being very small, and excluded from the wrist-joint by the interposition of an articular disk.
As illustrated in FIG. 1, the coronoid process 220 is a triangular eminence projecting forward from the upper and front part of the ulna 200, which forms a portion of the elbow joint. The base of the coronoid process is continuous with the body of the bone, and of considerable strength. Its apex is pointed, slightly curved upward, and, in flexion of the forearm, is received into the coronoid fossa of the humerus. Its upper surface is smooth and concave, and forms the lower part of the semilunar notch. Its antero-inferior surface is concave and marked by a rough impression for the insertion of the brachialis.
The coronoid process, among other functions, helps to resist posterior elbow subluxation. Fractures of the coronoid process of the ulna can occur in association with posterior dislocation of the elbow and valgus instability, since the medial collateral ligament (MCL) of the elbow inserts into the fracture fragment. Left untreated, the elbow joint of a patient can become unstable, stiff, and painful. In fact, stiffness is a common problem following this injury, as are post traumatic degenerative joint changes. In particular, patients with fracture of more than half of the coronoid process can lose over half of their range of elbow flexion-extension, and as few as one in five patients can expect to have a satisfactory recovery of function.
Accordingly, there remains a need for improved devices and methods for repairing coronoid process fractures in such a manner that the likelihood of recreating or reproducing a pain-free and fully functional elbow joint is maximized. It is an object of the present invention to provide such a device. This and other objects and advantages, as well as additional inventive features, will become apparent from the detailed description provided herein.